Search

Forest clearing in the vicinity of the Appalachian Trail National Park undermines the Trail's value as a wilderness retreat for millions of annual hikers. We estimate that 75,000 hectares of forest were lost to clearing during the decade of the 1990s inside a 16 km-wide corridor centered on the Trail. This loss represents 2.45 percent of forests within 8 km of the 3,500 km-long trail. Managed forest harvests in northern New England accounted for 76.8 percent of forest clearing. The factor most closely related to forest clearing is land ownership: only 0.29 percent of protected forests were cleared, while unprotected and managed forests were cleared at rates of 2.05 percent and 4.03 percent, respectively. A combination of boosted decision tree classifiers, multitemporal Kauth-Thomas transforms and the GeoCover Landsat dataset enabled a single, unfunded analyst to rapidly map land-cover change at 28.5- meter resolution within a 3.8 million hectare study area that spanned 16 Landsat scenes. [ABSTRACT FROM AUTHOR]

A sustainable management of non-renewable metals calls for scientific-ecological understanding of the regional material household. The copper household in the USA between 1900 and 2100 was chosen to illustrate mathematical modelling of such systems. Relatively limited and inaccurate sets of data already allow a first approximation of the metal management system. The copper fluxes of the 20th century have contributed to the formation of two new ore deposits of the same order of magnitude as the currently still available reservoir (90 million tons), i.e. copper stock in consumption products (approx. 70 million tons) and in landfills (approx. 40 million tons). The “landfill”, therefore, contains copper whose potential use is lost due to dilution. The long-term copper consumption stock is greater than the short-term stock. Scenarios show that the current economically mineable Cu-stocks will be exhausted in 30 to 50 years if a change in the existing management system does not occur. In case of a reorientation, the use of copper as a “new resource” in the consumption stocks appears to be the most promising strategy. The future waste management processes will have to increase their copper recycling rates. [ABSTRACT FROM AUTHOR]